light split along texture in cycles
Set the normal map to non-color data. This means that Blender will read it in linear space, which is what it expects for a normal map.
Also, please disconnect that alpha from the strength of the normal map unless you've got a good reason to have it there. It's (slightly) slowing down your render for probably no benefit.
If that normal map is ripped from the game, you might need to flip the green channel for it to show up correctly in Cycles. The fastest way to do this is to add an RGB curves node in the Cycles material (Add&gt;Color&gt;RGB Curves), click the G on the node so the curve only affects the green channel, and move the points at each end so the one on the left is at the top of the box and the one on the right is at the bottom of the box. This will make normal maps formatted for use with Unreal Engine 3 work better with Cycles' tangent space, although not perfectly. In the end the node should look like this:

Of course, you can also do this in a bitmap editor like Photoshop, Krita or GIMP.